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Knowing Nothing About Capacitance...

OK, I've had a table for 5 years now, have tried numerous phono stages and numerous carts, and am enjoying the hell out of my low-fi vinyl system. But after all this time, I'm still clueless about the relationships between cartridge specs and preamp specs.

For example, I'm now using an AT-OC9ml mk ii MC cart -- on the spec sheet it says that this cart's load capacitance is 20ohms. I picked up a vintage Denon integrated amp that I want to try -- it's MC phono section says that it's set for 100ohms. What does this mean? I know I can use the AT with the Denon, but I'm assuming that there will be some compromise in the match. (Whether it's an audible compromise, I have no idea.)

How does all this cart-preamp load matching work? Please keep it simple. I have a PhD, but it' not in anything like this. My scientific understanding peaked in 7th grade (40 years ago) and has gone downhill ever since.

Thanks,
Rich
winegasman
tvad
9,467 posts
 
You can change the load by using simple Y adapters and some loading plugs made from male RCA connectors and resistors of different values. I use this method with excellent results.

These are the adapters:
Dayton Y Adapter

You simply plug the loading plugs into one arm of each adapter, and you plug you phono interconnects into the other arm of each adapter. Change plugs until you find the sound that you prefer.

I made my loading plugs myself, but you can probably have a local tech make them for you.

Credit to Audiogon member Nsgarch, who taught me this method.
tvad
9,467 posts
 
Also, you can look up almost any cartridge on Cartridge Database.com and see the loading recommendation as well as weight and compliance specs.

BTW, 100 Ohms is a pretty low default loading value, IMO. Most phono sections default at 47kOhms, and some have options at 1000 Ohms, 100 Ohms and 10 Ohms.
rauliruegas
9,123 posts
 
Dear Rich: Maybe you make an error when you write the thread because capacitance is measured in uf not Ohms, Ohms are for impedance. Btw, 100 Ohms will be fine with your cartridge no problem about.

Regards and enjoy the music.
Raul.
winegasman OP
100 posts
 
Raul,

You're absolutely right -- I mistakenly said capacitance. The AT-OC9mlii says that the Recommended load impedance is 20 ohms. The Denon says that its MC phono stage is 100 ohms.

By the way, Tvad, the MM phono input for the Denon is 47k.

So, is the initial poster's statement accurate that at 100 ohms on the preamp side my cart is likely to sound brighter than it should?

Thanks to all of you for answering so quickly.
headsnappin's avatar
headsnappin
295 posts
 
Hey Rich, the loading you are referring to is impedance, measured in ohms, not capacitance. Moving coil cartridges are not affected by capacitance. You also cannot hurt anything by having the incorrect loading, just different tonal balance.
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